Through "Add Existing User By Email Address"

If the student is registered on Handshake, not in your user requests, and not connected to a different school, or if you accidentally rejected the original request, you can still add them by following these steps:

Go to Manage Students

On the manage students page, type their email into the "Add Existing User By Email Address"

Adding a new student

If the student doesn't have an account at all yet, you can add them with a new profile from the "Manage Students" page.

From that page, you can fill out the students details, and click create. The student will receive an email letting them know they have a new account.